When erecting a high rise building, with existing W-column designs, the W-columns are joined together (one on top of the other), using an erection process that requires the columns be joined together using a very slow multi-pass manual welding process. To improve the speed, quality, and economics of erecting steel framed buildings methods must be found to: (1) make full penetration welds attaching “base plates” to the bottom of the column flanges, whereby the base plate can, in turn, be bolted to piers or foundations; (2) weld the flanges of two W-columns together lengthwise (one on top of the other), using the Arcmatic® single-pass VertaSlag® welding process for a Welding Society Narrow Gap Electroslag Welding Method (ESW-NG)—welding both column flanges at the same time, using the fully automated programmable, computer controlled Arcmatic® VertSlag® welding process to replace the older manual multi-pass arc welding processes to speed up column splicing; (3) use four welded-on flange tabs, welded to the flanges of the two vertical W-columns that are being joined together, and vertical bars bolted together to temporarily hold the upper W-column flanges to the lower W-column flanges until the final single-pass Arcmatic® VertaSlag® welds can be used to permanently join the upper and lower W-column flanges together to speedup building erection process; and (4) to weld horizontal H-beams to W-column at each floor level moment area.
The number of columns welded (spliced) together, the available column length, and the number of moment connections on each column length depend on the number of columns in a structure's grid, the height of the structure, code and site requirements for the structure, engineering considerations for the structure, and transport limitations. Consider, for example, the erection of a building structure with a 20-foot available column length. Column splices must exist at every other story of the building. Assume the building is 8 columns wide by 8 rows deep forming a grid consisting of 8×8=64 columns, and the building is 40 stories. This building would require 40/2=20×64=1280 column splices. If each column splice averaged 30 man-hours (man-hours depends on the thickness of the column flanges) to weld using an existing multi-pass arc welding method, the total man-hours consumed would be expressed by the equation: (1280-splices)×(30 man-hours)=38,400 man-hours. If each man hour averaged approximately US-$75 per hour (depending on the thickness of the column flanges), the total cost to splice all of the columns is expressed by the equation: (US-$75×38,400 man-hours)=US$2,880,000.00.
If the existing cost of field splicing the W-column flanges together is US$2,880,000, the cost to erect a high rise steel frame building on site would be substantially reduced. In addition to the reduction in cost for splicing W-columns, the time required to erect the building would, in turn, be substantially reduced. For instance, there is a daily overhead cost to erect the building, if the frame can be erected faster by using the Arcmatic® W-column splicing method; the speed of all of the other construction details could also be increased, therefore decreasing the total construction time and expense.
There has never been a steel frame high rise building constructed using American Welding Society Narrow Gap Electroslag Welding Process (ESW-NG). There is no W-column in the art that provides the features and improvements amenable to constructing a steel frame high rise building using ESW-NG processes on site.
Thus, there is a need for an improved W-column design to erect a high rise steel frame building on site so where W-columns could be quickly aligned vertically allowing the temporary bolted connection to hold the vertically aligned W-columns together until the vertically aligned W-columns have been properly aligned, and welded with vertical Narrow Gap ElectroSlag or ElectroGas welding applications to permanently weld the W-column-to-W-column connections for corresponding vertically aligned W-columns.
There is a corresponding need for an improved W-column design to erect a high rise steel frame building on site where the W-column can carry increased stresses at a minimum cost.
There is yet another need for an improved W-column design to erect a high rise steel frame building on site that allows the Arcmatic® VertaSlag® ESW-NG welding process that uses a square-groove vertical welding connection that is in compliance with each applicable section and subsection of the AWS D1.1:2004 and AWS D1.8-05 Structural Welding Codes.